The concrete exterior of San Franciso's Coit Tower was damaged and the murals were being destroyed by water infiltrating the structure. Interactive Resources, Inc., Point Richmond, Calif., removed all loose or unsound concrete and material and sandblasted away concrete surrounding corroded rebars. Mechanical anchors supported deeper patches. Expanding the coal refuse-slurry impoundment dam at the Ohio Valley Coal Co.'s Powhatan Mine No. 6 involved raising the dam's height from 145 to 210 ft. Because the decant structure underneath was not strong enough to support the additional weight, GTech, Inc., Pittsburgh, sliplined the vulnerable portion of the channel with HDPE pipe. Project manager James Hamel has written a paper on the project, Rehabilitation of Decant Structure for Coal Slurry Impoundment in Ohio, for the American Institute of Mining, Metallurgical and Petroleum Engineers. Upgrading the drive system of Buffalo, N.Y.'s Ohio Street lift bridge meant installing state-of-the-art components that would retain the motion and power characteristics of the originals. The city's consultants, EI Associates, Buffalo, decided to replace the motors and controls, but retain the bridge's mechanical components. When the roof and columns of Valassis Inserts' Livonia, Mich. plant began to deform, the firm called in Broad, Vogt & Conant, Detroit, who devised a plan to strengthen the structure while maintaining full production.